Probably...with a 7pm ressie, you can expect to be seated around 7:30 -- even if you check in early. We had an 8:20 ressie, someone from our group checked in at 7:50, and we were seated around 8:50!! But we did get a WONDERFUL seat, so it was worth it!!
I've never felt rushed through a meal at 'Ohanas, so I wouldn't worry too much about that!!